Abstract
The light intensities of 15 kinds of recent light curing units were measured with time.The effects of changes in light intensity on polymerization of resin were evaluated by measuring the depth of cure in light-cured composite resins.The changes in light intensity with time were classified into 3 types.The light intensities on 3 light curing units were approximately constant with time, and those on the other 12 units were reduced with time.The depth of cure on composite resins was calculated from the reduced energy for a period of 10s after 290-s continuous emission.On the units in which light intensities were greatly reduced, the depth of cure was half that of the initial 10s after switching on.This suggested that the effects of variation of light intensity with time should be considered, when using light curing units.
